When the complaint is frequent infections, the assessment begins by determining whether the infections really are occurring more often than would be expected. Sleep routine, nutritional status, how blood sugar has been running, current medication and known chronic conditions are then addressed. Assessing these factors does not mean that a method of protection is being offered.
In adults, having an upper respiratory tract infection a few times a year is regarded as usual; particularly in people who have young children or who work in crowded settings, this number may be higher. The first step, then, is to establish whether the complaint really is above what would be expected.
The World Health Organization (opens in a new tab) reports that there are around one billion cases of seasonal influenza worldwide each year, that 3–5 million of these take a severe course, and that 290,000–650,000 respiratory deaths occur each year.
Who is at higher risk?
The World Health Organization lists the groups at higher risk of severe disease from seasonal influenza as follows:
- Pregnant women
- Children under 5 years of age
- People over 65 years of age
- People with chronic heart, lung, kidney, metabolic, neurological, liver or blood conditions
- People whose immune system is suppressed (HIV, chemotherapy, corticosteroid use, cancer)
- Health workers
The inclusion of metabolic conditions in this list explains why the course of blood sugar is assessed in people who present with a complaint of frequent infections. The World Health Organization (opens in a new tab) reports that, as of 2022, 830 million people worldwide were living with diabetes and that 59% of adults aged 30 and over living with diabetes were not taking medication for it that year; in other words, the possibility of going undiagnosed should not be overlooked.
What the assessment covers
The actual frequency and nature of the infections. How many times a year they occur, what type they are, how long they last, whether antibiotics were needed and whether there was a hospital admission are asked about.
The course of blood sugar. Undiagnosed diabetes, or diabetes that is not under control, is assessed separately.
Current medication. Corticosteroids and medicines that suppress the immune system are asked about.
Nutritional status. An inadequate and unbalanced diet, anaemia and iron status are assessed.
Sleep routine. Sleep duration and quality are asked about.
Smoking and environmental factors. Smoking, and time spent in crowded, enclosed and unventilated spaces, are asked about.
Known chronic conditions. Lung, kidney, liver and heart conditions are reviewed.
Whether there is a localised cause. If the infections keep recurring at the same site (for example, always the same sinus, always the same urinary tract), this is investigated separately.
In which patients is it assessed differently?
In the situations below, the assessment proceeds differently.
- In patients who are pregnant or breastfeeding (both the level of risk and the medicines that can be used are different)
- In patients receiving treatment that suppresses the immune system (follow-up is with the relevant specialty)
- In patients receiving active oncological treatment (the assessment is planned together with the specialty overseeing the treatment)
- In patients with a known immunodeficiency (follow-up is with the relevant specialty)
- In patients with a history of severe and recurrent infection (further assessment is needed)
- In patients over 65 who have more than one chronic condition (co-existing conditions and current medication are considered together)
- In patients under 18 years of age (the frequency of infection is assessed differently; this content has been prepared for adults)
Points to be aware of
This assessment does not offer a method of protection. The aim is to determine whether an issue that needs assessment lies behind the complaint of frequent infections.
Antibiotics are not needed for every infection. Antibiotic use is decided by the physician; do not take antibiotics on your own initiative or use leftover medicine.
Supplement use requires assessment by a physician. Taking a supplement when no deficiency has been demonstrated does not provide the expected contribution, and it may interact with your current medication. For details, see our article on supplement use.
The World Health Organization’s general precautionary recommendations are washing and drying the hands regularly, covering the mouth and nose when coughing or sneezing, disposing of tissues properly, staying at home when ill, and avoiding touching the eyes, nose and mouth.
The decision about vaccination is discussed with your physician. The World Health Organization states that vaccination is the principal way of protecting against influenza and recommends annual vaccination for high-risk groups. Whether it is suitable for you is determined by a physician’s assessment.
Results vary from person to person.
When should you see a physician without delay?
If you notice these symptoms, consult a physician without delay:
- Infections occurring markedly more often in a year than would be expected
- Infections that take a severe course or last a long time
- Infections that recur at the same site
- Infections in the mouth or on the skin that keep recurring
- Infections accompanied by unintentional weight loss, night sweats or persistent fatigue
- Wounds that heal slowly
- Frequent urination and excessive thirst developing alongside
In the event of a severe clinical picture accompanied by high fever, shortness of breath, altered consciousness or severe weakness, go directly to the emergency department.
Frequently asked questions
How many times a year counts as being ill too often?
In adults, an upper respiratory tract infection a few times a year is regarded as usual, and this number varies with living conditions. What matters is not the number alone; the severity of the infections, how long they last, whether they recur at the same site and how long recovery takes are also decisive. The assessment is made at the examination.
Does being ill often mean that my immunity is weak?
On its own it does not show that. Frequent infection may also be related to sleep routine, nutrition, the course of blood sugar, current medication, smoking and environmental factors. A known immunodeficiency is a different clinical picture and is assessed within the relevant specialty.
Should I take a vitamin or a supplement?
Starting one without a physician’s assessment is not recommended. Taking a supplement when no deficiency has been demonstrated does not provide the expected contribution. Tell your physician about every product you use.
Which tests are looked at in people who are ill often?
No standard list is applied. Depending on the complaint and the examination findings, a full blood count, blood sugar, iron and B12 status and, if needed, further investigations are usually assessed. Which of these are required is determined at the end of the examination.
Should I have the influenza vaccine?
The World Health Organization states that vaccination is the principal way of protecting against influenza and recommends annual vaccination for high-risk groups. Whether it is suitable for you is assessed by a physician, together with your existing conditions and your current medication.
Can I use the antibiotic I have left over?
No. Antibiotic use is decided by the physician. Unnecessary and incomplete use provides no benefit and contributes to antibiotic resistance.
Sources
- World Health Organization, Influenza (seasonal) fact sheet, 28 February 2025. https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal) (opens in a new tab)
- World Health Organization, Diabetes fact sheet, 14 November 2024. https://www.who.int/news-room/fact-sheets/detail/diabetes (opens in a new tab)
